Method for producing dry metal oxide compositions and coated substrates

ABSTRACT

The present invention generally relates to a process for making a metal oxide composition. The present invention also relates to a process for making a coated metal oxide substrate.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority from Provisional Application Ser. No.60/823,482 filed on Aug. 24, 2006, which is hereby incorporated byreference in its entirety. This application is a continuation-in-part ofU.S. patent application Ser. No. 11/844,196 filed Aug. 23, 2007.

FIELD OF THE INVENTION

The present invention generally relates to process for making a singleor mixed metal oxide composition powder. The powder includes oxides ofmetals, basic metal or metals, insoluble and soluble metal salts, andcombinations thereof. Resultantly, a tightly-adhered coated metal oxide,basic metal, or metal salt composition is formed. By oxidizing the basicmetal powder(s) along with other additives such as other basic metalpowders, metal oxide powders, and metal salts, the additives areincorporated into the resulting metal oxide composition powder andbecome part of the tightly adhered coating when substrates are used. Theprocess for formation requires agitation or mixing of the constituentswithout the need for heating, drying, or added processes, such ascalcining or forming of the product for use. The invention can be usedto treat fluid streams whereby the resulting metal oxide composition canreact with contaminants in a fluid stream comprised of gasses, liquids,and slurries.

BACKGROUND OF THE INVENTION

Natural and synthetic metal oxide compositions, such as iron oxide, havebeen used for a variety of applications. For example, it is well knownto use of metal oxides, particularly iron oxide (Fe_(x)O_(y)) and ZnO,in a reactor bed to remove contaminants, typically sulfur compounds,such as hydrogen sulfide (H₂S), from fluids, typically gas streams.Sulfur compounds are removed from fluids because they are knowncontaminants, which potentially make gas streams or other fluidsunsalable. Other uses of metal oxides and basic metals includes theremoval of arsenic, radioactive isotopes, and halogenated hydrocarbonsfrom water. Metal oxides are also used in a wide range of catalyticprocesses for chemical production and contaminant removal from variousfluids, such as, but not limited to, sulfur compounds, NO_(x) andSO_(x), CO₂.

There are a several processes used for making metal oxides fromwater-soluble metal salts including hydrothermal synthesis, hydrothermalprecipitation, flame hydrolysis, or thermal decomposition. All of theseprocesses, however, include multiple manufacturing steps that can beboth costly and time intensive. For example, hydrothermal synthesisincludes mixing an iron salt with a base solution, heating the solutionwith hot water, feeding the solution into a reactor for a sufficientamount of time to produce metal oxide particles, cooling the mixture,separating the metal oxide from the remaining solution, and drying themetal oxide particles. Flame hydrolysis includes vaporizing a metalhalide and transporting it in an inert gas into an oxy-hydrogen flame.The metal halide salt decomposes in the water producing flame to producea metal oxide.

Currently, powder coated metal oxide on substrates are used inflow-through packed-bed processes to react with and scavenge hydrogensulfide and thiols (mercaptans) present in natural gases and liquidhydrocarbons. There are several processes used to make loosely-adheredpowdered metal oxide moistened on substrates. Other processes requirebinding the metal oxide to a substrate with an adhesive or, calcining ordrying a metal oxide mixture onto a substrate. These processes includevarious manufacturing steps that can be both costly and time intensive.The process of binding the metal oxide to a substrate with an adhesiveor binding agents includes, for example, admixing zinc oxide withadhesives and processing the mixture into pellets, spheres, or flakes byextrusion. The calcining process includes soaking a substrate multipletimes in soluble metal oxide solutions and calcining or drying to createa specific metal oxide content on the substrate. As such, processes formaking a metal oxide composition that is a tightly-adhered coated metaloxide composition substrate and includes fewer manufacturing steps isdesired.

The resultant loosely-adhered powdered metal oxide coated substratescurrently being produced by simple moistening of the powdered metaloxide on a substrate described in the above processes also have severalproblems. For example, depending on the adhesive used, if any, to bindthe coated metal oxide to the substrate, the coating may degrade orseparate from the substrate thereby becoming less effective in theremoval of contaminants from fluids. In addition, the moistened powderedmetal oxides on substrates produced by current processes havelimitations as to the amount of metal oxide that can be coated onto thesubstrate. Typically, the processes are limited to less than 20% byweight metal oxide content on each substrate. The substrate must becarefully selected as the substrate can be important in maintaining themoistened powder metal oxide on the substrate. Many granular substratesare not suitable as they release the powdered metal oxide from thesubstrate during storage, drying, or when exposed to excessive moisture.Finally, it is believed that the hardness of the powdered metal oxideswetted on substrates currently is limited to substrates that are alreadyhard and are not further softened by moisture. The substrate hardness isnecessary to ensure the final product has sufficient crush strength tobe used in a packed bed. This means it is difficult to make a coatedproduct from a lightweight substrate, such as vermiculite and perlite.Additionally, non-porous substrates cannot be used as they resistmoistening that allows the metal oxide powder to attach and stick on thesubstrate. Also, most moisture sensitive substrates like calciumchloride are unavailable. Typically, use of such substrates results in aproduct that does not maintain its stability in packed-bed reactionvessels. As such, a process for coating a wide variety of substratesthat can achieve a high metal oxide content is desired. It is alsodesired to have a metal mixture on a substrate that is not easilyremoved.

SUMMARY OF THE INVENTION

The present invention relates to processes for making a metal oxidecomposition and a tightly-adhered metal oxide composition coatedsubstrate. The process for making a metal oxide composition typicallyincludes contacting a metal salt, a metal powder in a zero valence stateor basic metal powder, and a sufficient amount of water to initiate anoxidizing reaction between the metal salt and metal powder, withoutallowing the mixture to become a slurry or solution. Also, other metalpowders, metal oxides, and other additives may be added to create themetal oxide composition.

Typically, the process includes contacting a metal salt, with a solvent,such as water, to create a metal salt mixture. The metal salt can besoluble or dispersible in water. Next, a sufficient amount of the metalsalt mixture is reacted with a metal powder, such as iron powder, toinitiate an oxidizing reaction between the metal powder and the metalsalt mixture thereby forming the metal oxide composition. Typically, theratio of metal powder to metal salt mixture is from about 1:2 to about50:1 by weight. The resultant metal oxide composition is a free-flowing,i.e. non-clumping powder, that is ready for use without furtherprocessing or drying. Other additives, such as other basic metals, metaloxides, can be incorporated into the metal oxide composition by mixingwith the metal powder to be oxidized before the metal salt mixture isadded. Additionally, this process allows the use of byproducts of otherprocesses and recovered waste materials as the basic metal powder, metalsalt, other additives or combinations thereof.

Essentially, the same process can achieve the same results by dry mixingthe metal salt with the metal powder and other additives, followed byadding a small amount of solvent to initiate the oxidizing reaction.This can be done alone or in the presence of a substrate whereby themetal oxide composition forms primarily on and somewhat inside thesubstrate depending on the porosity of the substrate creating a tightlybound metal oxide composition on almost any substrate. Additionally, thebasic metal powder and other additives, such as non-reactive metalpowders or other metal oxides and other powders, can be mixed along witha substrate, whereby the substrate may be pre-moistened with solvent andthen the metal salt solution or slurry in water is added and mixed.Depending on the degree of porosity of the substrate, the metal oxidecomposition coats and penetrates substrates with greater porosity andcoats the outside of substrates with little or no porosity. When softsubstrates that are easily crushed before treatment, such as granularvermiculite or perlite, are subjected to the formation of the metaloxide composition on the substrate, the resulting metal oxidecomposition coating hardens the treated granular product allowing it tobe used in packed-bed filters for treatment of fluids withoutdegradation or softening.

The process for making the metal oxide composition is performed atambient conditions and only requires agitation. The resultant metaloxide composition may be used as is to remove contaminants, such assulfur compounds from a fluid, or, the composition can be coated onto asubstrate prior to use.

The present invention also relates to a process for making atightly-adhered and penetrated coated metal oxide substrate, wherein thesubstrate includes up to about 75% or more by weight metal oxidecomposition. Typically, this process includes contacting a metal salt, ametal powder in a zero valence or basic state, and a sufficient amountof water or solvent to initiate an oxidizing reaction between the metalsalt and metal powder, as described above. The metal salt and metalpowder mixture oxidation is initiated and then the oxidizing mixture iscontacted with a substrate, such as lime or calcined montmorillonite,and a sufficient amount of moistening agent, such as water, alcohol, orother liquids. The moistening agent is used to evenly distribute themetal oxide composition over the surface of the substrate as it oxidizesand form a tightly-adhered coating primarily on and somewhat within thesubstrate. This process is performed at ambient conditions and onlyrequires agitation or mixing. The moistening with a second solvent wetsthe substrate, allowing the oxidizing metal powder to adhere to thesubstrate while continuing the oxidation process. Typically, the coatedmetal oxide substrate is allowed to complete the oxidation process atambient conditions, with the process generally taking between 15 minutesand 24 hours. Formation depends on the speed of oxidation, amount andstrength of metal salt, and formation of the coating on the substrate.

The resultant tightly-adhered coated metal oxide composition on asubstrate may be used to remove contaminants, such as sulfur compounds,NO_(x), SO_(x), CO₂, and arsenic, heavy metals, halogenated compoundsand radioactive compounds from fluids. The resultant coated metal oxidesubstrate has a metal oxide content of from about 1% to about 75% byweight, thereby having the capability of a higher amount of reactivematerial than current coated metal oxide substrates. Lightweightsubstrates can be selected to allow a density of less than about 1 gramper cubic centimeter with 20% or more metal oxide content. Thetightly-adhered coating on the lightweight substrate, such asvermiculite or perlite, becomes sufficiently hardened to support thegranular packed bed depths of 3 feet or more into the reaction vesselwithout collapse or degradation of the granular material under its ownweight which causes plugging. Additionally, this tightly-adhered metaloxide coating on a substrate by this process allows much higher fluidflow through a granular bed without degradation or stripping of metaloxide powder by the fluids as experienced with loosely-adhered simplemetal oxide powder moistened on substrate. In particular, the metaloxide composition coats the substrate to form a coated product. Thismeans the product essentially forms a continuous shell or coating aroundthe substrate, that can withstand a flow rate of water at 3.0inches/minute in a packed reactor vessel

Other powders, such as basic metals, metal oxides, and powderedadditives can be incorporated or mixed with the initiated oxidizingmetal oxide mixture and moistened onto a substrate together whereby theadditive powder is incorporated into the tightly-adhered coating on thesubstrates in small amounts of powder additive to basic metal ratios ofup to 5 to 1 powdered additive to oxidizing metal oxide mixturerespectively.

Additionally, multiple coatings of the same or different metal oxidecompositions can be placed on a substrate. Also, used metal oxidecompositions on substrates can be easily re-coated and used again forthe same purpose or in another contaminant removal process.

REFERENCE TO COLOR FIGURES

The application file contains at least one photograph executed in color.Copies of this patent application publication with color photographswill be provided by the Office upon request and payment of the necessaryfee.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1A depicts the formation of an iron oxide composition by treating150 g of basic iron powder with a mixture of 20 g of water and 5 g ofcopper chloride dihydrate (CuCl₂-2H₂O) for 1 hour.

FIG. 1B depicts that treating 150 g of basic iron powder with a mixtureof 20 g of water and 5 g of sodium chloride (NaCl) for 1 hour, thesodium chloride did not oxidize the iron powder.

FIG. 1C depicts that treating 150 g of basic iron powder with 20 g ofwater after 1 hour wherein the iron powder was not oxidized.

FIG. 2A depicts the formation of an iron oxide composition by treating150 g of basic iron powder with a mixture of 20 g of water and 5 g ofCuCl₂-2H₂O for 6 hours.

FIG. 2B depicts treating 150 g of basic iron powder with a mixture of 20g of water and 5 g of NaCl for 6 hours whereby the iron powder did notoxidize.

FIG. 2C depicts that treating 150 g of basic iron powder with 20 g ofwater after 6 hours whereby the iron powder did not oxidize.

FIG. 3A depicts the formation of an iron oxide composition by treating150 g of basic iron powder with a mixture of 20 g of water and 5 g ofCuCl₂-2H₂O for 24 hours.

FIG. 3B depicts that treating 150 g of basic iron powder with a mixtureof 20 g of water and 5 g of NaCl for 24 hours whereby the iron powderdid not oxidize.

FIG. 3C depicts that treating 150 g of basic iron powder with 20 g ofwater whereby after 24 hours the iron powder did not oxidize.

FIG. 4A depicts raw granular carbon.

FIG. 4B depicts raw granular carbon coated with iron oxide as describedin Example 1.

FIG. 5A depicts granular vermiculite.

FIG. 5B depicts granular vermiculite coated with iron oxide as describedin Example 2.

FIG. 6A depicts crushed rock.

FIG. 6B depicts crushed rock coated with iron oxide as described inExample 3.

FIG. 7A depicts polished rock.

FIG. 7B depicts polished rock coated with iron oxide as described inExample 4.

FIG. 8 depicts calcined clay coated with iron oxide as described inExample 5.

FIG. 9 depicts the iron oxide coated calcined clay after reacting itwith H₂S as described in Example 5.

FIG. 10 depicts the re-coated iron oxide calcined clay as described inExample 7.

FIG. 11 depicts the iron oxide coated wood as described in Example 10.

FIG. 12A depicts the zinc oxide coated lime as described in Example 11A.

FIG. 12B depicts the iron oxide coated calcium chloride as described inExample 11B.

FIG. 12C depicts the iron oxide coated lime as described in Example 110.

FIG. 13A depicts the iron oxide/zinc oxide coated calcined claydescribed in Example 13A.

FIG. 13B depicts the iron oxide/zinc oxide coated calcined claydescribed in Example 13B.

FIG. 13C depicts the iron oxide/zinc oxide coated calcined claydescribed in Example 13C.

FIG. 14 depicts the tin oxide/iron oxide coated calcined clay describedin Example 13D.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a process for making a metal oxidecomposition that is a substantially formed at dry ambient conditionswithin between about 15 minutes and about 24 hours. The composition isformed by reacting the metal salt mixture and basic metal powdertogether, with or without other additives, to form a free-flowing,non-clumping, powder. The present invention also relates to a processfor making a tightly-adhered metal oxide composition formed from ametal/metal-oxide/additive, coating on a substrate having a metal oxidecomposition content of up to 75% by weight. The resultant coated metaloxide composition on a substrate may be used to remove contaminants,such as sulfur and heavy metal compounds, from fluids. Additionally,multiple coatings can be made of the same or different metal oxidecompositions on substrates. The substrates can be optionally recoatedwith the metal oxide composition so that, in effect, the composition isre-coated and used again. This can reduce the quantity of productdisposed of in a landfill thereby protecting the environment andreducing cost by substituting used material for new substrates.

I. Metal Oxide Composition

The process for making a metal oxide composition can be initiated bycontacting an amount of a metal salt with an amount of an aqueoussolvent to form a metal salt mixture or slurry. Any of a variety ofmetal salts may be used in the present invention. As used herein, ametal salt is a metal of any chloride, carbonate, sulfate, acetate,nitrate, chelate, phosphate, oxide, and combinations thereof. Asmentioned a metal powder may also be mixed in. The metal ion of themetal salt may be any metal, however, it is preferred for the metal tohave an equal or higher than electropotential as compared to the basicmetal of the metal powder. The metal ion includes platinum, gold,silver, copper, cadmium, nickel, zinc, palladium, lead, chrome, iron,titanium, manganese, magnesium, tin, cobalt, or mixtures thereof. Forexample, the metal salt may be copper chloride, ferric chloride, sodiumchloride, silver nitrate, copper sulfate, cobalt acetate, nickel-cobaltsulfate, zinc phosphate, iron phosphate and nickel phosphate. Theaqueous solvent that is contacted with the metal salt may be selectedfrom the group consisting of water, or a water/alcohol mixture. Forexample, the alcohol may be glycol or isopropanol.

Any method of mixing the metal salt and the solvent may be used so longas the two are thoroughly mixed and the metal salt is at least partiallysolubilized or disperses in the initial solvent. For example, a metalsalt, such as copper chloride dihydrate, may be contacted with water, inany suitable vessel, at ambient conditions, and agitated to partially orfully dissolve the metal salt. Typically, the ratio of metal salt tosolvent when making the metal salt mixture is from about 4:1 to about1:4 by weight. Generally, the metal salt and solvent are contacted forfrom about 10 seconds to about 90 minutes mixed in a continuous processto form a solution or dispersion in the solvent.

Once the metal salt mixture has been prepared, a sufficient amount ofthe metal salt mixture is reacted with a metal powder, in a zero valenceor basic state, to initiate an oxidizing reaction between the metalpowder and the metal salt mixture thereby forming a metal oxidecomposition. The amount of solvent in the metal oxide composition islimited so that the metal oxide composition does not become a slurry orsolution, essentially, no free moisture is present. Rather, theresultant metal oxide composition is a free-flowing, or non-clumpingpowder that is ready for use without further processing or drying.

As used herein, the metal powder may be any metal powder that is in azero valence state, i.e. non-oxidized state. The metal used may comefrom a wide variety of sources, including semi-processed metal, scrapmetal, reduced foundry dust, and byproducts of metal working facilities,all which reduce costs, waste, or disposal of materials. Suitable typesof metals that may be used include one or more metals or metalloidsselected from the group consisting of a group 1A element, a group 2Aelement, a group 1B element, a group 2B element, a group 3B element, agroup 4B element, a group 5B element, a group 6B element, a group 7Belement, a group 8B element, a group 3A element, a group 4A element, agroup 5A element, a group 6A element, rare earth metals, metal oxides,and combinations thereof. Alternatively, the metal powder may be analloy of the above metals. Suitable metal powders, for example, includeiron powder, zinc powder, tin powder, nickel powder, aluminum powder,antimony powder, chrome, and combinations thereof. Typically, the metalpowder has an average diameter of less than about 2 mm. Alternatively,the metal powder has an average diameter of less than about 1 mm.

Any method of reacting the metal salt mixture and the metal powder maybe used so long as the two are thoroughly mixed and an oxidizingreaction occurs between the metal salt mixture and the metal powder.When the solution is added it is preferred for a slurry or solution tonot be formed. Throughout the oxidizing process, the metal powder heatsand expands as it oxidizes to a partial or complete metal oxide powder,or composition. For example, the metal salt mixture may be reacted witha metal powder, such as iron powder, in a suitable vessel having anagitation device such that the metal salt mixture and metal powder arethoroughly mixed and an oxidation reaction is initiated. Typically, thereaction is conducted at ambient conditions and in a ratio of metalpowder to metal salt mixture of from about 1:2 to about 50:1 by weight.Alternatively, the ratio of metal powder to metal salt mixture is about15:1 by weight. Typically, the initiation of oxidation reaction betweenthe metal salt mixture and the metal powder may take from about 5minutes to about 1 hour and the metal oxide composition will besubstantially dry at the end of the reaction from 30 minutes to 24hours.

Alternatively, the process for making a metal oxide composition includescontacting the metal powder, metal salt, and aqueous solventconcurrently in a suitable vessel having an agitation device such thatthe metal salt, metal powder, and aqueous solvent are thoroughly mixedand an oxidation reaction is initiated. The reaction is conducted atambient conditions and in a ratio of metal powder to metal salt mixtureof from about 1:2 to about 50:1 by weight and a ratio of metal salt tosolvent from about 20:1 to 1:20. As described before, the aqueoussolvent is used to at least partially solubilize, or disperse, the metalsalt initiating an oxidation reaction between the metal salt mixture andthe metal powder. Similarly, the amount of aqueous solvent is limited sothat the metal oxide composition does not become a slurry or solution.Typically, the initiation of oxidation reaction between the metal saltmixture and the metal powder may take from about 5 minutes to about 1hour and the metal oxide composition will be substantially dry at theend of the reaction from 30 minutes to 24 hours.

The process for making a metal oxide composition of the presentinvention may also be adjusted to form a metal oxide composition thatincludes two or more metal oxides. One process may, for example, includereacting a metal salt mixture, such as a copper chloride and watermixture, with two or more distinct metal powders, such as zinc powderand iron powder, to form a metal oxide composition having two or moremetals, such as an iron oxide/zinc oxide composition. In anotheralternative, the metal salt mixture, such as a copper chloride and watermixture, may be reacted with a first metal powder, such as iron powder,and then reacted with a second metal powder, such as a zinc powder, toform a metal oxide composition having two or more metals, such as aniron oxide/zinc oxide composition. In yet another alternative, theprocess may include contacting the metal salt mixture with a metal and ametal oxide powder or other non-reactive powders (not reactive to themetal salt) such that the resultant metal oxide composition include twoor more metal oxides, basic metals, or incorporates other additives orcombination. Such a process may, for example, include reacting a metalsalt mixture, such as a copper chloride and water mixture, with a firstmetal powder, such as iron powder, and then reacting it with a metaloxide powder, such as iron oxide powder to form a metal oxidecomposition having a metal and a metal oxide mixture, such as aniron/iron oxide composition. Still another alternative, the basic metalpowder, metal salt, and non-reactive powders and/or metal oxides aremixed together along with sufficient moisture to cause basic metalpowder and metal salt to react and thereby incorporating thenon-reactive powder and metal oxides into the final metal oxidecomposition. Non-reactive powders can be diatomaceous earth or clays(calcined or natural); or metals such as copper, molybdenum, titanium,gold, silver or alloys such as bronze, brass, stainless steels, etc.

As described above, the resultant metal oxide composition is afree-flowing powder and non-clumping powder, that is ready for usewithout further processing or drying. The resultant metal oxidecomposition may be used as is to remove contaminants from fluids.Conversely, the metal oxide composition may be coated onto a carrier orsubstrate. It should be noted that the density of the resulting metaloxide composition is similar to the density of commercially availablepigments indicating a high surface area is created.

II. Coated Metal Oxide Substrate

The present invention is also directed to a process for making atightly-adhered metal oxide composition coated substrate, wherein themetal oxide substrate composition comprises up to about 75% by finalweight. Generally, the process for making a coated metal oxide substrateincludes contacting a metal salt and an aqueous solvent to form a metalsalt mixture, reacting a sufficient amount of the metal salt mixturewith a metal powder to initiate the oxidation of the metal powder,contacting the metal powder and metal salt mixture, i.e. the oxidizingmetal composition, with a substrate, and adding a sufficient amount of asecond moistening agent to the metal oxide composition and substratemixture to evenly, or uniformly, coat the oxidizing metal oxidecomposition mixture onto the substrate. Most any substrate can be coatedwith the metal oxide composition can be used in the present invention.Even water or liquid sensitive substrates that would normally degrade ordissolve when exposed to an aqueous solution and/or heat or substratesthat are initially soft or easily crushed may be used. It is believed,that as the metal oxide continues to oxidize around the wettedsubstrate, a tight bond or matrix is formed between the metal oxideparticles and the substrate. As such, as the metal oxide coatingincreases the hardness of the substrate or its resistance to crushing.Suitable substrates include, but are not limited to, desiccationproducts, natural products, and synthetic products. Desiccation productsinclude calcium chloride, calcium oxide, silica gel, silica-based beads,activated alumina, alumina-gel balls, activated bauxite, molecularsieves, raw or calcined natural zeolites, synthetic zeolites, andcombinations thereof. Suitable natural products include raw or activatedcarbon, partially or fully calcined vermiculite, rock, raw or calcinedclay, wood, coconut shell chip or coir, coal, raw or bloated shale, rawor calcined diatomaceous earth, and lime. Alternatively, the substratemay be an inert carrier material such as a calcined montmorillonite. Thesolvent may be the same solvent used to make the metal salt mixture orit may be different. Typically, for a water-sensitive substrate themoistening agent is an alcohol or similar non-aqueous liquid.

Any method of reacting the metal powder, metal salt mixture, moisteningagent, and the substrate may be used so long as the moistening agent atleast partially wets the surface of the substrate and the metal powdercontinues to oxidize forming a tight bond or matrix with the substrateas the metal oxide mixture continues oxidation. For example, the metalpowder and metal salt mixture may be reacted with the substrate and amoistening agent in a suitable vessel having an agitation device, atambient conditions, and in a ratio of metal powder to metal salt mixtureof from about 1:2 to about 50:1 by weight and a ratio of metal salt tosolvent from about 20:1 to 1:20, and a metal powder, metal salt, andsolvent composition ratio of about 1:20 to 20:1. The metal powder tosubstrate ratio is less than 20:1, 19:1, 18:1, 17:1, 16:1, 15:1, 14:1,13:1, 12:1, 11:1, 10:1, 9:1, 8:1, 7:1, 6:1, 5:1, 4:1, 3:1, 2:1 or lessdepending upon the substrate. Typically, the metal powder, metal saltmixture, substrate, and second solvent are mixed or agitated for fromabout 5 minutes to about 6 hours. The coated metal oxide composition onthe substrate is then allowed to oxidize at ambient conditions for fromabout 15 minutes to about 24 hours prior to use.

Alternatively, the process for making a coated metal oxide substrateincludes mixing a metal salt, metal powder, and any other additives witha substrate concurrently and then adding the solvent while mixing atambient conditions to form a coated metal oxide composition on asubstrate. The ratio of metal powder to metal salt mixture of from about1:2 to about 50:1 by weight a ratio of metal salt to solvent from about20:1 to 1:20, with the metal oxide composition being about 5 to 75% byweight on the final product. Typically, the metal salt, solvent, metalpowder, additives and a substrate are reacted for from about 5 minutesto about 16 hours. The coated metal oxide substrate is then allowed tofurther oxidize at ambient conditions for from about 8 hours to about 24hours prior to use or packaging.

In another alternative, the process for making a coated metal oxidecomposition on a substrate of the present invention may be used toregenerate or re-coat a metal oxide substrate that already has a metaloxide coating or has been spent, i.e. the metal oxide coating isdepleted. This simply involves the above process but the substrate hasspent metal oxide coated on its surface. The same mixture or differentmixtures may be used on the substrate with the recoated or spent metaloxide coating. This allows multiple metal oxide coatings and thecontinued use of the substrate reducing the cost of purchasing newcoated metal oxide substrates and reducing the cost of disposing of thespent substrate thereby limiting the environment impact. It is alsoanticipated that sufficient metal or metal oxide content can be achievedon the new or used substrate making the final product attractive torecycle operations such as fertilizer blending operations or metalrecovery.

Examples of the resultant tightly-adhered metal oxide composition coatedsubstrate of the present invention include an iron oxide coated rawcarbon, an iron oxide coated vermiculite, an iron oxide coated crushedrock, an iron oxide coated polished rock, an iron oxide coated calcinedclay, a red iron oxide/iron oxide coated calcined clay, a black ironoxide/iron oxide coated calcined clay, an iron oxide coated wood sawdust, a zinc oxide coated lime, an iron oxide coated lime, an iron oxidecoated calcium chloride, an iron oxide coated silica gel, an ironoxide/zinc oxide coated calcined clay, among others.

The resultant coated metal oxide substrate includes from about 5% toabout 75% by weight metal oxide composition and from about 25% to about95% by weight substrate. For example, an iron oxide coated calcinatedmontmorillonite substrate coated by the process of the present inventionincludes about 35% by weight iron oxide and 65% by weight calcinatedmontmorillonite. Alternatively, the coated metal oxide composition on asubstrate of the present invention may be coated one or more additionaltimes to produce a coated metal oxide composition on a substrate thatincludes more than 75% by weight metal oxide composition, such as about80%, 85%, 90%, 95% or more. Importantly, the substrate is coated. Thisessentially means that the substrate is completely covered with themetal oxide composition and that the composition is held in contact withthe substrate, such that it does not readily separate from the substratedue to contact with a fluid stream. Further, the coatings can be foundin the pores on the substrate. Practically speaking, coating meansforming a nearly continuous layer around a substrate, with the coatingheld in contact with the substrate regardless of conditions.Furthermore, the coating is not readily removed upon contact with afluid flowing in a reactor vessel. For example: The flow rate of fluidsthrough a column, are calculated by open bed (rising velocity of fluidsin a column without material) of the following fluids:

Open Bed Rising Fluid Velocity in Inches Per Minute Fluid as Liquids 10C. or 50 F. 38 C. or 100 F. Water 3.0 5.5 Gasoline 4.3 7.5 Butane 12 14Propane 17 19Under these flow rates the metal oxide composition is not removed.

The resultant coated metal oxide composition on a substrate has severaluses. One use for the coated substrate is for sulfur removal,particularly H₂S removal from fluids, such as natural gas. Typically, inthis case a vessel is packed with the coated substrate and as the sulfurrich natural gas passes through the vessel the gas reacts with the oxidecoating removing the sulfur from the natural gas and producing a sulfurfree gas. Alternatively, the coated metal oxide substrate may be usedfor the reduction of NO_(x), SO_(x), CO_(x), halogenated hydrocarbons,treatment of radioactive wastes, heavy metal removal or reduction, andcatalytic reactions of hydrocarbons.

The following examples are simply intended to further illustrate andexplain the present invention. The invention, therefore, should not belimited to any of the details in these examples.

EXAMPLES Example 1 Metal Oxide Coated Raw Carbon

The following experiment was conducted to form an iron oxide coatedgranular raw carbon by the process of the present invention.

3 g of copper chloride dihydrate were added to 6 g of water tosolubilize or partially dissolve the copper chloride dihydrate atambient conditions. The metal salt mixture was then added to 75 g ofcommercial iron powder, mixed, and allowed to start oxidizing for about15 minutes. 30 g of granular raw carbon (0.35 g/cc) were then added tothe powder and mixed. 19 g of additional water were then added and mixedto bond the oxidizing powder to the carbon. The finished product wasdried for 8 hours without additional processing.

The iron oxide coated carbon included 38% by weight iron or about 55% asiron oxide Fe₂O₃. The density of the iron oxide was 0.53 g/cc. Thefinished iron oxide coated carbon was hard and not easily broken orcrushed as compared to the starting raw granular carbon.

Example 2 Metal Oxide Mixture on Granular Vermiculite

The following experiment was conducted to form an iron oxide coatedgranular vermiculite by the process of the present invention.

3 g of copper chloride dihydrate were added to 6 g of water tosolubilize or partially dissolve the copper chloride dihydrate atambient conditions. The metal salt mixture was then added to 75 g ofcommercial iron powder, mixed, and allowed to oxidize for about 15minutes. 30 g of granular vermiculite (0.11 g/cc) were then added to thepowder and mixed. 14 g of additional water were then added and mixed toaffix the oxidized powder to the vermiculite. The finished product wasdried for 8 hours without additional processing.

The iron oxide vermiculite included 59% by weight iron or about 84% asiron oxide Fe₂O₃. The density of the iron oxide was 0.23 g/cc. Thefinished iron oxide coated vermiculite was hard and not easily broken orcrushed as compared to the starting raw granular vermiculite.

Example 3 Metal Oxide Mixture on Crushed Rock

The following experiment was conducted to form an iron oxide coatedcrushed rock by the process of the present invention.

3 g of copper chloride dihydrate were added to 6 g of water tosolubilize or partially dissolve the copper chloride dihydrate atambient conditions. The metal salt mixture was then added to 75 g ofcommercial iron powder, mixed, and allowed to oxidize for about 15minutes. 250 g of crushed rock were then added to the powder and mixed.9 g of additional water were then added and mixed to affix the oxidizedpowder to the rock. The finished product was dried for 12 hours and wasready for use without additional processing.

The iron oxide crushed rock included 22% by weight iron or about 31% asiron oxide Fe₂O₃.

Example 4 Metal Oxide on Polished Rock

The following experiment was conducted to form an iron oxide coatedpolished rock by the process of the present invention.

3 g of copper chloride dihydrate were added to 6 g of water tosolubilize or partially dissolve the copper chloride dihydrate atambient conditions. The metal salt mixture was then added to 75 g ofcommercial iron powder, mixed, and allowed to oxidize for about 15minutes. 250 g of polished rock were then added to the powder and mixed.9 g of additional water were then added and mixed to affix the oxidizedpowder to the rock. The finished product was dried for 12 hours and wasready for use without additional processing.

The iron oxide polished rock included 22% by weight iron or about 31% asiron oxide Fe₂O₃.

Example 5 Metal Oxide on Calcined Clay

An iron oxide coated calcined clay was tested for its ability to removehydrogen sulfide from contaminated air.

3 g of copper chloride dihydrate were added to 6 g of water tosolubilize or partially dissolve the copper chloride dihydrate atambient conditions. The metal salt mixture was then added to 75 g ofcommercial iron powder, mixed, and allowed to oxidize for about 15minutes. 100 g of calcined clay were then added to the powder and mixed.50 g of additional water were then added and mixed to affix theoxidizing powder to the clay. The finished product was dried for 8 hoursand was ready for use without additional processing.

The iron oxide coated calcined clay included 59% by weight iron or about84% as iron oxide Fe₂O₃. The density of the iron oxide was 0.67 g/cc.

Example 6 H₂S Removal Test

A 1-inch tube that was 30 inches long was filled with 185 g of the ironoxide coated calcined clay formed according to Example 5. Air withvariable amounts of H₂S was passed through the tube, from top to bottom,at a flow rate of 1 to 1.25 liters per minute (about 14 to 18 secondstotal contact time).

The table below shows the removal of H₂S during a total time of 54hours. The amount of H₂S in the inlet and outlet air was measured usinggastec stain tubes.

Time Inlet H₂S Outlet Wave Front (1) 1 Hour 30 ppm 0 ppm 2 inches 2Hours 60 ppm 0 ppm 2 inches 3 Hours 700 ppm 0 ppm 3 inches 5 Hours 200ppm 0 ppm 2 inches 6 Hours 200 ppm 0 ppm 2 inches 7 Hours 250 ppm 0 ppm2 inches 8 Hours 1400 ppm 0 ppm 5 inches 10 Hours 400 ppm 0 ppm 3 inches12 Hours 1400 ppm 0 ppm 5 inches 18 Hours 4500 ppm 0 ppm 10 inches 22Hours 500 ppm 0 ppm 7 inches 24 Hours 3500 ppm 0 ppm 10 inches 27 Hours3750 ppm 0 ppm 10 inches 30 Hours 1500 ppm 0 ppm 8 inches 31 Hours 700ppm 0 ppm 5 inches 32 Hours 800 ppm 0 ppm 6 inches 34 Hours 800 ppm 0ppm 6 inches 40 Hours 400 ppm 0 ppm 5 inches 43 Hours 200 ppm 0 ppm 4inches 44 Hours 500 ppm 0 ppm 6 inches 45 Hours 200 ppm 0 ppm 5 inches46 Hours 12000 ppm 0 ppm 20 inches 48 Hours 12000 ppm 0 ppm 21 inches 51Hours 1400 ppm 0 ppm 12 inches 52 Hours 200 ppm 0 ppm 6 inches 53 Hours500 ppm 0 ppm 7 inches 54 Hours 500 ppm 0 ppm 7 inchesAs the H₂S reacted with the red iron oxide, it turned the iron oxideblack, which illustrated the distance the H₂S penetrated down thecolumn. As the amount of H₂S on the inlet increased, the distance theH₂S penetrated the column increased. As the amount of H₂S decreased, thedistance the H₂S penetrated the column was reduced as noted by thechange in color of the media as it returned from black to red. Also,note that after 54 hours the H₂S continued to be removed.

Example 7 Recoated Metal Oxide on Calcined Clay from Example 5

The following experiment was conducted to recoat the spent iron oxidecoated calcinated clay from Example 5 by the process of the presentinvention.

3 g of copper chloride dihydrate were added to 6 g of water tosolubilize or partially dissolve the copper chloride dihydrate atambient conditions. The metal salt mixture was then added to 75 g ofcommercial iron powder, mixed, and allowed to oxidize for about 15minutes. 120 g of used iron oxide coated calcined clay from Example 5were then added to the powder and mixed. 27 g of additional water werethen added and mixed to affix the oxidized powder to the calcined clay.The finished product was dried for 8 hours and was ready for use withoutadditional processing.

The iron oxide recoated calcined clay included 60% by weight iron orabout 85% as iron oxide Fe₂O₃ (not including previously coated ironoxide mixture). The density of the iron oxide was 0.8 g/cc.

Example 8 Iron Oxide/Red Iron Oxide on Calcined Clay

The following experiment was conducted to form an iron oxide/red ironoxide coated calcined clay by using a metal powder, iron powder, and ametal oxide powder, red iron oxide powder.

2 g of copper chloride dihydrate were added to 4 g of water tosolubilize or partially dissolve the copper chloride dihydrate atambient conditions. The metal salt mixture was then added to 40 g ofcommercial iron powder, mixed, and allowed to oxidize for about 15minutes. 40 g of red iron oxide powder were then added to the ironpowder and mixed. 100 g calcined clay were then added to the commercialiron and red iron powder mixture and mixed. 33 g of additional waterwere then added and mixed to affix the oxidized powders to the clay. Thefinished product was dried for 84 hours and was ready for use withoutadditional processing.

Example 9 Iron Oxide/Black Iron Oxide on Calcined Clay

The following experiment was conducted to form an iron oxide/black ironoxide coated calcined clay by using a metal powder, iron powder, and ametal oxide powder, black iron oxide powder.

2 g of copper chloride dihydrate were added to 4 g of water tosolubilize or partially dissolve the copper chloride dihydrate atambient conditions. The metal salt mixture was then added to 40 g ofcommercial iron powder, mixed, and allowed to oxidize for about 15minutes. 40 g of black iron oxide powder were then added to thecommercial iron powder and mixed. 100 g of calcined clay were then addedto the commercial iron and black iron oxide powder mixture and mixed. 33g of additional water were then added and mixed to affix the oxidizedpowders to the clay. The finished product was dried for 84 hours and wasready for use without additional processing.

Example 10 Metal Oxide on Wood Saw Dust

The following experiment was conducted to form an iron oxide coated woodsawdust by the process of the present invention.

3 g of copper chloride dihydrate were added to 6 g of water tosolubilize or partially dissolve the copper chloride dihydrate atambient conditions. The metal salt mixture was then added to 75 g ofcommercial iron powder, mixed, and allowed to oxidize for about 15minutes. 20 g of wood saw dust were then added to the powder and mixed.20 g of additional water were then added and mixed to affix the oxidizedpowder to the wood sawdust. The finished product was dried for 12 hoursand was ready to break into smaller pieces for use without additionalprocessing. The iron oxide coated wood included 63% by weight iron orabout 90% as iron oxide Fe₂O₃. The density of the iron oxide was 1.3g/cc.

Example 11A Zinc on Pelletized Lime

The following experiment was conducted to form a zinc oxide coatedpelletized lime by the process of the present invention.

2 g of copper chloride dihydrate were added to 3 g of water tosolubilize or partially dissolve the copper chloride dihydrate atambient conditions. The metal salt mixture was then added to 70 g ofcommercial zinc powder and mixed. The powder was then immediately addedto 150 g of lime and mixed. 15 g of isopropanol were then added to thelime and powder mixture, mixed, and allowed to air-dry for 30 minutes.The iron oxide coated lime included 31% by weight zinc or about 38% aszinc oxide, ZnO.

Example 11B Iron on Pelletized Lime

The following experiment was conducted to form an iron oxide coatedpelletized lime by the process of the present invention.

3 g of copper chloride dihydrate were added to 6 g of water tosolubilize or partially dissolve the copper chloride dihydrate atambient conditions. The metal salt mixture was then added to 70 g ofcommercial iron powder, mixed, and allowed to oxidize for about 15minutes. 150 g pelletized lime were then added to the powder and mixed.15 g of isopropanol were then added to the powder and lime mixture andmixed to affix the oxidized powder to the lime. The finished product wasdried for 3 hours and was ready for use without additional processing.The iron oxide coated lime included 31% by weight iron or about 44% asiron oxide Fe₂O₃.

Example 11C Iron on Pelletized Calcium Chloride

The following experiment was conducted to form an iron oxide coatedpelletized calcium chloride by the process of the present invention.

3 g of copper chloride dihydrate were added to 6 g of water tosolubilize or partially dissolve the copper chloride dihydrate atambient conditions. The metal salt mixture was then added to 70 g ofcommercial iron powder, mixed, and allowed to oxidize for about 15minutes. 120 g of pelletized calcium were then added to the powder andmixed. 10 g of isopropanol were then added to the powder and calciummixture and mixed to affix the oxidizing powder to the calcium in apartially opened container or bag. (Note—If pelletized calcium chloridewas exposed to humid air or moisture for a few minutes, it wouldliquefy). The finished product was dried for 6 hours and was ready foruse without additional processing.

Example 12A Iron Oxide on Silica Gel

The following experiment was conducted to form an iron oxide coatedsilica gel by the process of the present invention.

3 g of copper chloride dihydrate were added to 6 g of water tosolubilize or partially dissolve the copper chloride dihydrate atambient conditions. The metal salt mixture was then added to 75 g ofcommercial iron powder, mixed, and allowed to oxidize for about 15minutes. 150 g of silica gel were then added to the powder and mixed. 9g of additional water were then added to the powder and gel mixture andmixed to affix the oxidized powder to the gel. The finished product wasdried for 8 hours and was ready for use without additional processing.

Example 12B Zinc Oxide on Silica Gel

The following experiment was conducted to form a zinc oxide coatedsilica gel by the process of the present invention.

1 g copper chloride dihydrate was added to 3 g of water to solubilize orpartially dissolve the copper chloride dihydrate at ambient conditions.The metal salt mixture was then added to 75 g of commercial zinc powderand mixed. 150 g silica gel were added to the powder and mixed. 9 g ofadditional water were then added to the powder and gel mixture and mixedto bond the oxidized powder to the gel. The finished product was driedfor 1 hour and was ready for use without additional processing.

Example 13A Iron Oxide/Zinc Oxide on Calcined Clay

The following experiment was conducted to form an iron oxide/zinc oxidecoated calcined clay by the process of the present invention. The ironpowder and zinc powder were contacted with the copper chloride dihydrateand water mixture concurrently.

2.5 g copper chloride dihydrate were added to 5 g water to solubilize orpartially dissolve the copper chloride dihydrate at ambient conditions.The metal salt mixture was then mixed into a mixture of 35 g ofcommercial zinc powder and 35 g of commercial iron powder. 100 g ofcalcined clay were then added to the powder mixture and mixed. 20 g ofadditional water were then added to the powder and clay mixture andmixed to affix the oxidized powders to the clay. The finished productwas dried for 1 hour and was ready for use without additionalprocessing.

The zinc acted as galvanizing where little red iron oxide could be seenwhen the basic zinc and iron were mixed, then oxidized. The product is amixture of basic iron powder and zinc oxide coating on the substrate.

Example 13B Iron Oxide/Zinc Oxide on Calcined Clay

The following experiment was conducted to form an iron oxide/zinc oxidecoated calcined clay by the process of the present invention. The ironpowder was first contacted with the copper chloride dihydrate and watermixture and then contacted with the zinc powder.

2.5 g of copper chloride dihydrate were added to 5 g of water tosolubilize or partially dissolve the copper chloride dihydrate atambient conditions. The metal salt mixture was then added to 35 g ofcommercial iron powder, mixed and allowed to oxidize for 15 minutes. 35g commercial zinc powder were then added to the iron powder and mixed.100 g of calcined clay were then added to the iron and zinc powdermixture and mixed. 20 g of additional water were added to the ironpowder, zinc powder, and clay mixture and mixed to affix the oxidizedpowders to the gel. The finished product was dried for 3 hours and wasready for use without additional processing.

Some iron oxides could be seen when the basic iron was allowed topartially oxidize first. This product was a mixture of basic iron andiron oxides with zinc oxide coating on the substrate.

Example 13C Iron Oxide/Zinc Oxide on Calcined Clay

The following experiment was conducted to form an iron oxide/zinc oxidecoated calcined clay by the process of the present invention. The ironpowder was first contacted with the copper chloride dihydrate and watermixture and then contacted with the calcined clay. The iron oxide coatedcalcined clay was then contacted with the zinc powder.

2.5 g of copper chloride dihydrate were added to 5 g of water tosolubilize or partially dissolve the copper chloride dihydrate atambient conditions. The metal salt mixture was then added to 35 g ofcommercial iron powder, mixed and allowed to oxidize for 15 minutes. 100g of calcined clay were then added to the powder and mixed. 20 g ofadditional water were then added to the powder and clay mixture andmixed to affix the oxidized powder to the clay and let sit for 15minutes. 35 g of commercial zinc powder was then added to the iron oxidecoated clay and mixed. The finished product was dried for 3 hours andwas ready for use without additional processing.

The basic iron oxidation was nearly complete and then basic zinc wasapplied and oxidized. This product was mostly iron oxide with possiblysome basic iron with zinc oxide on the substrate.

As can be seen from the above example, the degree of oxidation of one ormore metal powders in a basic metal mixture, was controlled to achievevarying degrees of metal oxidation, especially where one or more of themetals was catholically protective to one or more of the other basicmetals present in the mixture.

Example 13D Iron Oxide/Tin Oxide on Calcined Clay

The following experiment was conducted to form an iron oxide/tin oxidecoated calcined clay by the process of the present invention. The ironpowder and tin powder were contacted with the copper chloride dihydrateand water mixture concurrently.

4 g of copper chloride dihydrate were added to 6 g of water tosolubilize or partially dissolve the copper chloride dihydrate atambient conditions. The metal salt mixture was then added and mixed witha powder mixture of 35 g of commercial tin powder and 35 g commercialiron powder and allowed to oxidize for about 15 minutes. 100 g ofcalcined clay were then added to the powder mixture and mixed. 20 g ofadditional water were then added to the powder and clay mixture andmixed to affix the oxidized powders to the clay. The finished productwas dried for 8 hours and was ready for use without additionalprocessing.

The products produced according to the above examples were analyzed onthe substrate to determine the composition make-up.

The phases constitute the majority components in the sample analyzed andpossible secondary/trace phases likely in 2 to 5% by weight ranges.

Example 14 Best Matches from ICDD/ICSD Data Bases

Metal oxide compositions were produced from basic iron powder alone andin combination with added iron oxides, alone and on a substrate such asnatural zeolite. Where a substrate was used, the coating was abraded toremove the metal oxide composition from the surface of the particlesbefore analyzing. The compositions were mixed and allowed to oxidize for24 hours before packaging for analysis.

An x-ray diffraction test was conducted by Evans Analytical Group usingstandard protocols.

Sample Primary Phases Possible Secondary/Trace phases 1BFeO(OH)—Lepidocrocite Fe₈(O,OH)₁₆Cl_(1.3)—Akaganeite-M Iron OxideHydroxide Monoclinic I2/m Orthorhombic Bbmm FeO(OH)—GoethiteFe₃O₄—Magnetite Orthorhombic Pbnm Cubic Fd3m Fe(OH,Cl)_(2.55)—IronChloride This sample is oxidized iron powder Hydroxide—Green Rust usingthe following formula: Rhombohedral R 50 grams iron powder Fe—Iron 1gram copper chloride Cubic Im3m 1 gram water 2A Fe₃O₄—MagnetiteFeO(OH)—Lepidocrocite Cubic Fd3m Iron Oxide Hydroxide FeO(OH)—GoethiteOrthorhombic Bbmm Orthorhombic Pbnm Fe₈(O,OH)₁₆Cl_(1.3)—Akaganeite-MThis sample is oxidized iron powder Monoclinic I2/m using the followingformula: Fe(OH,Cl)_(2.55)—Iron Chloride 25 grams iron powderHydroxide—Green Rust 1 gram copper chloride Rhombohedral R 1 gram waterFe—Iron 100 grams of granular zeolite Cubic Im3m 10 grams of water Note:metal oxide coating removed before analysis. 3B FeO(OH)—GoethiteFe(OH,Cl)_(2.55)—Iron Chloride Orthorhombic Pbnm Hydroxide—Green Rust(Fe,Ni)—Taenite Rhombohedral R Cubic Fm3m Fe—Iron This sample isoxidized iron powder Cubic Im3m using the following formula:Ca(SO₄)(H₂O)₂—Gypsum 50 grams iron and nickel powder Monoclinic C2/c 1gram copper sulfate Fe₃O₄—Magnetite 1 gram water Cubic Fd3m 4AFe₃O₄—Magnetite FeO(OH)—Lepidocrocite Cubic Fd3m Iron Oxide HydroxideFeO(OH)—Goethite Orthorhombic Bbmm Orthorhombic PbnmFe(OH,Cl)_(2.55)—Iron Chloride This sample is oxidized iron powderHydroxide—Green Rust using the following formula: Rhombohedral R 25grams iron powder Fe—Iron 1 gram copper sulfate Cubic Im3m 1 gram waterPDF# 00-006-0696 100 grams of granular zeolite 10 grams of water Note:metal oxide coating removed before analysis. 4B Fe₃O₄—MagnetiteFeO(OH)—Lepidocrocite Cubic Fd3m Iron Oxide Hydroxide This sample isoxidized iron powder Orthorhombic Bbmm and synthetic iron oxide mixusing the FeO(OH)—Goethite following formula: Orthorhombic Pbnm 12.5grams iron powder Fe(OH,Cl)_(2.55)—Iron Chloride 12.5 grams syntheticmagnetite Hydroxide—Green Rust 1 gram copper chloride Rhombohedral R 1gram water Fe₈(O,OH)₁₆Cl_(1.3)—Akaganeite-M 100 grams of granularzeolite Monoclinic I2/m 10 grams of water Fe—Iron Note: metal oxidecoating removed Cubic Im3m before analysis. 5A Fe₃O₄—MagnetiteFeO(OH)—Lepidocrocite Cubic Fd3m Iron Oxide Hydroxide FeO(OH)—GoethiteOrthorhombic Bbmm Orthorhombic Pbnm Fe₈(O,OH)₁₆Cl_(1.3)—Akaganeite-MThis sample is oxidized iron powder Monoclinic I2/m and natural ironoxide mix using the Fe(OH,Cl)_(2.55)—Iron Chloride following formula:Hydroxide—Green Rust 12.5 grams iron powder Rhombohedral R 12.5 gramsnatural magnetite Fe—Iron 1 gram copper chloride Cubic Im3m 1 gram water100 grams of granular zeolite 10 grams of water Note: metal oxidecoating removed before analysis. 5B Fe₃O₄—Magnetite FeO(OH)—GoethiteCubic Fd3m Orthorhombic Pbnm FeO(OH)—Lepidocrocite Fe—Iron Iron OxideHydroxide Cubic Im3m Orthorhombic Bbmm Fe₈(O,OH)₁₆Cl_(1.3)—Akaganeite-MMonoclinic I2/m Fe(OH,Cl)_(2.55)—Iron Chloride Hydroxide—Green RustRhombohedral R This sample is oxidized iron powder and iron oxide mixusing the following formula: 12.5 grams iron powder 10 grams syntheticmagnetite 10 grams natural magnetite 1 gram copper chloride 1 gram water100 grams of granular zeolite 10 grams of water Note: metal oxidecoating removed before analysis. 6 Fe₃O₄—Magnetite Fe(OH,Cl)_(2.55)—IronChloride Cubic Fd3m Hydroxide—Green Rust FeO(OH)—Goethite Rhombohedral ROrthorhombic Pbnm Ca(SO₄)(H₂O)₂—Gypsum This sample is oxidized ironpowder Monoclinic C2/c and iron oxide mix using the following Possible:formula: Fe₂Si₂O₅(OH)₄ × 12.5 grams iron powder 2H₂O—Hisingerite 10grams synthetic magnetite Monoclinic P 10 grams natural magnetite 1 gramcopper sulfate 1 gram water 100 grams of granular zeolite 10 grams ofwater Note: metal oxide coating removed before analysis. 7AFe₃O₄—Magnetite FeO(OH)—Goethite Cubic Fd3m Orthorhombic Pbnm Thissample is oxidized iron powder Ca(SO₄)(H₂O)₂—Gypsum and iron oxide mixusing the Monoclinic C2/c following formula: Fe(OH,Cl)_(2.55)—IronChloride 12.5 grams iron powder Hydroxide—Green Rust 12.5 grams metalphosphate Rhombohedral R 1 gram copper chloride Possible Trace: 1 gramwater CaAl₂Si₂O₈ × 4H₂O—Gismondine 100 grams of granular zeoliteMonoclinic P21/c 10 grams of water Heulandite—CaKAlSiO × H2O Note: metaloxide coating removed Monoclinic C2/m before analysis. 8FeO(OH)—Lepidocrocite Fe₈(O,OH)₁₆Cl_(1.3)—Akaganeite-M Iron OxideHydroxide Monoclinic I2/m Orthorhombic Bbmm Fe₃O₄—MagnetiteFeO(OH)—Goethite Cubic Fd3m Orthorhombic Pbnm Fe(OH,Cl)_(2.55)—IronChloride Hydroxide—Green Rust Rhombohedral R This sample is oxidizediron powder and iron oxide mix using the following formula: 12.5 gramsiron powder 12.5 grams metal phosphate 100 grams of granular zeolite 10grams of water Note: metal oxide coating removed before analysis. Thetable above lists the compounds identified with highest figure of meritfrom the ICDD/ICSD data bases. Although the basic phases are similar forthe set of samples, the relative amounts of the phases differsignificantly for the individual samples. In order to emphasize this,the table above is separated into two columns. The first column liststhe primary phase, and the second column lists secondary and tracephases. Typically, primary phases are responsible for >70% of the totaldiffraction intensity. Note that, given the complexity of the XRDpatterns, it is possible that some trace phases were not identified.Also, in many cases, the (OH) and Cl are substitutable into the matrix,and without elemental analysis verifying the presence of Cl, the actualformulas may have (OH) groups present instead of Cl. Note that the NMRreadings are excluded.

The invention illustratively disclosed herein suitably may be practicedin the absence of any element, which is not specifically disclosedherein. It is apparent to those skilled in the art, however, that manychanges, variations, modifications, other uses, and applications to themethod are possible, and also changes, variations, modifications, otheruses, and applications which do not depart from the spirit and scope ofthe invention are deemed to be covered by the invention, which islimited only by the claims which follow.

What is claimed is:
 1. A process for making a metal oxide coatedsubstrate for use in removing contaminants from fluid streams, theprocess comprising: a. contacting a metal salt with a first aqueoussolvent to form a metal salt mixture, wherein the ratio of solvent tometal salt is from 20:1 to 1:20 by weight; b. reacting a sufficientamount of the metal salt mixture with an amount of metal powder in azero valence state at ambient conditions to initiate an oxidizingreaction between the metal powder and the metal salt mixture to form anoxidizing mixture; c. contacting the metal powder and metal salt mixturewith a substrate, wherein the ratio of metal powder to substrate is lessthan 12:1; and, d. optionally adding a sufficient amount of a secondsolvent to moisten the substrate and adhere an oxidizing metal oxidecomposition onto the substrate wherein the oxidizing reactionsubstantially proceeds forming a uniformly, metal oxide coated substratecomprising from at least 5% to more than 95% by weight metal oxide foruse in removing contaminants from fluid streams.
 2. The process of claim1, wherein the metal salt is selected from the group consisting of metalchloride, carbonate, sulfate, acetate, nitrate, chelate, phosphate,oxide, and combinations thereof.
 3. The process of claim 2, wherein themetal salt is selected from the group consisting of: copper chloride,iron chloride, sodium chloride, nickel chloride, manganese chloride,magnesium chloride, copper sulfate, iron sulfate, zinc sulfate, nickelsulfate, manganese sulfate, magnesium sulfate, zinc phosphate, nickelphosphate, iron phosphate, aluminum phosphate, titanium oxide, magnesiumphosphate, and combinations thereof.
 4. The process of claim 1, whereinthe first aqueous solvent is selected from the group consisting of waterand a water/alcohol mixture.
 5. The process of claim 1, wherein themetal powder is selected from the group 2A, 3B, 4B, 5B, 6B, 7B, 8, 1B,2B, 3A, 4A, 5A, metals, rare earth metals, and combinations thereof. 6.The process of claim 5, wherein the metal powder is selected from thegroup consisting of: iron powder, zinc powder, tin powder, copperpowder, aluminum powder, antimony powder, magnesium powder, titaniumpowder, manganese powder, molybdenum powder, chromium powder, nickelpowder, cobalt powder, platinum powder, and combinations thereof.
 7. Theprocess of claim 1, wherein the ratio of metal powder to metal salt isfrom about 1:2 to about 50:1 by weight.
 8. The process of claim 1,wherein the metal salt and the first aqueous solvent are contacted forfrom about 5 seconds to about 10 minutes.
 9. The process of claim 1,wherein the ratio of metal powder and metal salt mixture to substrate tothe second solvent is from about 20:1:10 to about 1:30:1 by weight. 10.The process of claim 1, wherein the metal salt mixture and the metalpowder are reacted for from about 15 minutes to about 24 hours.
 11. Theprocess of claim 1, wherein the metal powder is added to the moistenedsubstrate followed by the metal salt mixture.
 12. The process of claim1, wherein the metal powder and metal salt are added to the moistenedsubstrate and allowed to react for 15 minutes to 24 hours.
 13. Theprocess of claim 1, wherein the substrate is at least one desiccationproduct.
 14. The process of claim 13, wherein the desiccation productsare selected from the group consisting of calcium chloride, calciumoxide, silica gel, silica-based beads, activated alumina, alumina-gelballs, activated bauxite, molecular sieves, natural zeolites, syntheticzeolites, and combinations thereof.
 15. The process of claim 1, whereinthe substrate is selected from the group consisting of carbon,vermiculite, rock, clay, calcinated clay wood, coconut shell chip orcoir, coal, shale, diatomaceous earth, recovered synthetic zeolite,alumina, and lime.
 16. The process of claim 1, wherein the substrate iscalcinated montmorillonite.
 17. The process of claim 1, wherein thesecond solvent is selected from the group consisting of water, alcohol,hydrocarbons, halogenated hydrocarbons, and combinations thereof. 18.The process of claim 1, wherein the metal powder and metal salt mixture,the substrate, and the second solvent are contacted for from about 15minutes to about 24 hours.
 19. The process of claim 1, wherein thesubstrate is a spent metal oxide coated substrate.
 20. The process ofclaim 1, wherein the metal salt mixture is reacted with a second metalpowder.
 21. The process of claim 20, wherein the second metal powder isa metal powder in a zero valence state or is a metal oxide powder. 22.The process of claim 1, wherein the metal oxide coated substrate has adensity of less than about 1 gram/cubic centimeter.